1. Field of the Invention
The present invention relates to an arrangement of a magnetic disk.
2. Description of the Prior Art
Conventionally, a magnetic disk having a center hub as shown in FIGS. 1 and 2 has been used. Reference numeral 1 designates a disk-like magnetic storage medium, and 2 a center hub fixed to the disk-like magnetic storage medium 1. The storing into and reproducing from the disk-like magnetic storage medium 1 is performed in such a manner that a driving spindle 11 is inserted as shown in FIG. 3 into a circular center hole 2a formed at the central portion of the center hub 2 so as to rotate the center hub 2 to thereb rotate the disk-like magnetic storage medium 1 which is fixed to the center hub 1. However, the cener hole 2a of the center hub 2 of the conventional magnetic disk is cylindrically shaped as shown in FIG. 2 and therefore it is necessary to provide such an arrangement as shown in FIG. 3 in order to fix the magnetic disk to a magnetic storage device. That is, such a mechanism as shown in FIG. 3 is employed, in which the driving spindle 11 is inserted into the center hole 2a of the center hub 2 until an abutment surface 11b of the driving spindle 11 is urged against an under abutment surface 2b of the center hub 2, and, further, a hub pressing 12 is urged downward in the drawing by any means such as a compression spring 14 to thereby urge an abutment surface 12a of the hub pressing 12 against an upper abutment surface 2c of the center hub 2.
In such a conventional fixing mechanism, however, when a magnetic disk is fixed, it is necessary to move the hub pressing 12 upward in the drawing by any means to widen the distance between the hub pressing 12 and the driving spindle 11 to be larger than the thickness of the center hub 2 so as to enable the center hub 2 to be displaced left/right in the drawing to insert the driving spindle 11 into the center hole 2a of the center hub 2, and the hub pressing 12 is moved again downward in the drawing while the driving spindle is being inserted or after it has been inserted into the center hole 2a of the center hub 2, resulting in not only complication in mechanism but worse working property in magnetic disk mounting.